21689287776 has 432 divisors, whose sum is σ = 71218719936. Its totient is φ = 6220836864.

The previous prime is 21689287693. The next prime is 21689287777. The reversal of 21689287776 is 67778298612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21689287777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 93086956 + ... + 93087188.

It is an arithmetic number, because the mean of its divisors is an integer number (164858148).

Almost surely, 2^21689287776 is an apocalyptic number.

21689287776 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21689287776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35609359968).

21689287776 is an abundant number, since it is smaller than the sum of its proper divisors (49529432160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21689287776 is a wasteful number, since it uses less digits than its factorization.

21689287776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355 (or 321 counting only the distinct ones).

The product of its digits is 28449792, while the sum is 63.

The spelling of 21689287776 in words is "twenty-one billion, six hundred eighty-nine million, two hundred eighty-seven thousand, seven hundred seventy-six".